diff options
Diffstat (limited to 'share/man')
-rw-r--r-- | share/man/man4/tcp.4 | 13 | ||||
-rw-r--r-- | share/man/man7/tuning.7 | 15 |
2 files changed, 28 insertions, 0 deletions
diff --git a/share/man/man4/tcp.4 b/share/man/man4/tcp.4 index bd3b755..1024271 100644 --- a/share/man/man4/tcp.4 +++ b/share/man/man4/tcp.4 @@ -343,6 +343,19 @@ This value should not generally be modified but may be used to set a global per-connection limit on queued data, potentially allowing you to intentionally set a less then optimum limit to smooth data flow over a network while still being able to specify huge internal TCP buffers. +.It tcp.inflight_stab +The bandwidth delay product algorithm requires a slightly larger window +then it otherwise calculates for stability. This parameter determines the +extra window in maximal packets / 10. The default value of 20 represents +2 maximal packets. Reducing this value is not recommended but you may +come across a situation with very slow links where the ping time +reduction of the default inflight code is not sufficient. If this case +occurs you should first try reducing tcp.inflight_min and, if that does not +work, reduce both tcp.inflight_min and tcp.inflight_stab, trying values of +15, 10, or 5 for the latter. Never use a value less then 5. Reducing +tcp.inflight_stab can lead to upwards of a 20% underutilization of the link +as well as reducing the algorithm's ability to adapt to changing +situations and should only be done as a last resort. .El .Sh ERRORS A socket operation may fail with one of the following errors returned: diff --git a/share/man/man7/tuning.7 b/share/man/man7/tuning.7 index 092658b..eead2a8 100644 --- a/share/man/man7/tuning.7 +++ b/share/man/man7/tuning.7 @@ -587,6 +587,21 @@ only effects data transmission (uploading / server-side). It does not effect data reception (downloading). .Pp +Adjusting +.Va net.inet.tcp.inflight_stab +is not recommended. +This parameter defaults to 20, representing 2 maximal packets added +to the bandwidth delay product window calculation. The additional +window is required to stabilize the algorithm and improve responsiveness +to changing conditions, but it can also result in higher ping times +over slow links (though still much lower then you would get without +the inflight algorithm). In such cases you may +wish to try reducing this parameter to 15, 10, or 5, and you may also +have to reduce +.Va net.inet.tcp.inflight_min +(for example, to 3500) to get the desired effect. Reducing these parameters +should be done as a last resort only. +.Pp The .Va net.inet.ip.portrange.* sysctls control the port number ranges automatically bound to TCP and UDP |